PRODUCTION OF YOUNG OAK-BARK. 487 



because its numerous bundles of bast penetrate the sapwood 

 deeply, and render peeling very difficult, it is of little value. 



(b) Locality. — It may be stated as a rule proved by expe- 

 rience, that not only the quantity, but also the quality of oak- 

 bark is directly proportional to the energy of the coppice- 

 growth, for quickly grown, vigorous oak-shoots produce most 

 tannic acid. The percentage of tannic acid for oaks of equal 

 age is directly proportional to the thickness of the bast and cor- 

 tex, and this is known to depend on the greater or less vigour of 

 their growth. The nature of the locality is therefore the most 

 important factor in the yield. If the oak, when compared with 

 many other trees, has a very limited range in which it is at its 

 best, this is even more marked with oak-bark coppice. A mild 

 climate and a loose, sufficiently moist and miuerally rich warm 

 soil are essential conditions for this to be remunerative. 



The climate is undoubtedly the chief factor in the production 

 of tannin. All tanning materials are the richer in tannic acid, 

 the more southern the country in which they are produced ; 

 this is the case with galls and other substances, and is equally 

 true for oak-bark. The mild climate of the Rhine-valley and the 

 adjoining districts, especially the Moselle-valley, Rheingau, the 

 district of the Saar and the Odenwald, aflfords the best oak-bark 

 coppices in Germany. Oak-bark is also produced commercially 

 in the Silesian hills. Saxony, the North German plain, Bruns- 

 wick, Mecklenburg, &c., but it cannot compete with Rhenish 

 bark. Many districts in Austria are more favourably situated 

 for successful production of bark, which is there produced in 

 fairly large quantities. Districts where the vine is cultivated in 

 the open, or where at any rate the better classes of fruit trees 

 flourish, may be cited as suitable for a remunerative yield of oak- 

 bark. The richer the soil in suitable mineral matter, the better, 

 provided it is sufficiently porous ; for the demands of the oak on 

 heat require a loose soil easily capable of being heated. Wet, 

 even damp places are not suitable for oak-coppice. Most oak- 

 coppices are on southerly aspects of hills, on Bunter sandstone, 

 Grauwacke, Argillaceous schist, porphyry or limestone, or on 

 gravels in the wide river-valleys.* 



* [From the above, it is evident that oak-bark coppice should prove more 

 renunierative in the south of England, ^\' iles, and in Ireland, than in Scotland. 

 -Tu.] 



